The present invention relates to the process of inserting sliders onto slide zippers used on reclosable plastic bags and, more particularly, to an apparatus which pre-positions and feeds a fixed number of sliders to the slider insertion area of a slider insertion device with the fixed numbers of sliders based on the requirements of the slider insertion device.
Reclosable bags having slide zippers are generally more desirable to consumers than bags which have traditional interlocking zippers, since such bags are perceived to be easier to open and close than slider-less zippers. As a result, slide zippers for use with plastic bags are numerous and well-known in the reclosable fastener art. Typical slide zippers comprise a plastic zipper having two interlocking profiles and a slider for engaging and disengaging the interlocking profiles of the zipper.
Methods and apparatuses for manufacturing reclosable plastic bags using reclosable zippers with a slider are also well-known in the art. Known slider loaders include the Hugues reference (U.K. Patent No. 2,085,519) and the LaGuerve references (U.S. Pat. Nos. 3,701,191 and 3,701,192) as well as the slider insertion device provided in the application filed Mar. 11, 2002; entitled xe2x80x9cINSERTION APPARATUS FOR ATTACHING SLIDERS ONTO ZIPPER BAGS AND FILMxe2x80x9d. Typically, a loading rack providing a supply of sliders to a slider insertion area is attached as part of the slider loader or slider insertion apparatus. As such, the use of loading racks with slider loaders or other insertion devices is fairly well-developed in the prior art, but nevertheless remains open to improvements contributing to an increased efficiency and cost-effectiveness during the manufacture of reclosable bags.
An improvement to the use of loading racks is to provide a feed tube and sender apparatus in which sliders are pneumatically transported in predetermined amounts from a supply of sliders to the loading rack. By transporting and positioning the sliders in such a manner, the amount of jamming of the sliders during transport to the loading rack is reduced. A reduction in jamming thereby reduces downtime of the slider insertion apparatus or loader as well as the maintenance problems associated with the downtime.
A further improvement is to provide an optional loading rack as part of the feed tube and sender apparatus. The loading rack would pneumatically guide the sliders from the feed tube to an insertion area of a slider insertion apparatus. By pneumatically guiding the sliders, the possible amount of jamming of the sliders in the loading rack is reduced.
Accordingly, the present invention provides a slider feed apparatus for transporting sliders from a supply of sliders to a slider insertion area of a slider insertion device. The slider feed apparatus generally includes a sender track, a feed tube, an optional loading rack, and a controller. In the slider feeding process, a first sensor on the sender track detects a lack of sliders in the sender track. A signal is sent from the first sensor to a controller. The controller turns on a vibratory bowl and actuates a first solenoid-operated plunger, thereby releasing a quantity of sliders from a supply of sliders in the vibratory bowl to a slider entry port of the sender track.
Once the first sensor detects that the sender track has an adequate quantity of sliders, the controller turns off the vibratory bowl. Once released from the vibratory bowl to the sender track, air connections pneumatically push the sliders along the sender track to a second solenoid-operated plunger.
A second sensor is connected to the loading rack to detect a lack of sliders in the loading rack. Upon detecting a lack of sliders, the second sensor signals the controller. The controller actuates the second solenoid-operated plunger and a solenoid-operated pneumatic valve. Upon actuation, the second solenoid-operated plunger opens a passage in the sender track and the pneumatic valve opens to provide an air blast in the sender track, thereby launching a group of sliders out of the sender track into the feed tube. The first solenoid-operated plunger, in a corollary function, prevents sliders from being pushed back into the vibratory bowl by closing the passage back to the vibratory bowl when the pneumatic valve is actuated to open.
As the group of sliders passes from the sender track to the feed tube and further on to the loading rack, the loading rack is filled or the quantity of sliders required is met. The second sensor detects that the quantity of sliders is sufficient and then signals the controller to actuate the pneumatic valve and the solenoid-operated plungers to a closed position. This process repeats itself as sliders are being used during insertion.
The loading rack guides the sliders from the feed tube to an insertion area of a slider insertion apparatus or loader. The loading rack includes multiple angular air connections for directing air flow that pneumatically move the sliders along the loading rack. In addition to the second sensor, a third sensor is provided as a backup to signal the controller in case spacing occurs between sliders because of rebounding caused during the feeding of the sliders.